Cylinder drainage and relief valve



May 17 1927.

F. C. MILLER CYLINDER DRAINAGE AND RELIEF VALVE Filed Feb. 17. 1922 III Patented May 1 FRANK c. ivrILLE This invention relates to a drainage relief valve for ste CYLINDER DRAINAGE Ann RELIEF VALVE.

Application filed February 17, 1922. Serial No. 537,288.

and

am engine cylinders, the

device being particularly useful when applied to the" eyhndersof locomotives.

It is the object of my invention to provide an improved construction of valve for such purposes which will be simple and economical in construction and reliable in operation and which will fully protect the cylinder under all conditions of operation.

With this general object in view, my invention in its preferred form comprises a valve casing suitably connected to the cylinder clearance space and also to'a supply of live steam from inder and the engine throttle. ential piston is freely ber within the casing and a point between the cyl- A differslidable in the chamage-or outlet opening therein.

In the-preferred form, a restricted passage is provided which connects the portions ofthe valvechamber on the opposite sides of the differential piston; As shown in the drawings, his restricted passage is formed through tl location of this passage may This restricted passage permits cushioning of the action of the piston and also provides drainage varied.

connection.

Further features dlcated 1n the dra itself, but the re piston be considerably for the steam inlet of my invention are inmore wings and will be particularly pointed out in the "appended claims. I

A preferred form of my invention is shown in the drawings in which Fig. 1 is a side cylinder with my thereto;

Fig. 2 is a of the valve;'

Fig. 3' is a simi elevation of an engine lmproved valve applied longitudinal sectional elevation lar view with the parts in a different position; and

Fig. 4: is an enlarged sectional view the shut-off valve mechanism.

Referring to the drawings, my improved 10 having a champortions 11 and 12 and a connecting passage 13. A pipe 14." leads from the space 11 to the clearance space 16 leads from the may be connected of the engine cylinder 15 and a pipe a point in the throttle The passage 18 to which a drainage or drip pipe space 12 to controls a drains ATENTorrict.

BQ OF .AUBURNDALE, MASSACHUSETTS.

19. A separate valve is. used for each end of the cylinder but these valves may have a common connection with the steam supply, as shown 1n F 1g. 1.

A difl'erentialplston 2 0 is slidab'le in the casing 10,- the smaller portion of'the differential piston litting'the passage 13' and the larger portion fitting the chamber portion 12.

Lugs 21 on the inner end of a plug 22 prevent the differential piston 20, from seatthe chamber ing lirnny against the end of 12, so that the steam enteringthrough the pipe 16 may have accessto the whole ad is provided between the This opening23 is quite restricted being preferably only 1/64 of an inch in diameter when the diameter of the engine cylinder is from 20 to28 inches.- WVith a '20 inch cylinderthe ratio ofthe area of the passage to the engine cylinder is something like 1 to 1,600,000. 7 a v A shu't-off valve 24 may be placed in the upward'connection 16 for a purpose to be described. This valve is normally, held open by a spring but has a pipe and valve 26 (Fig. 1) by which it is connected to a source of air or steam pressure for closing the valve when desired. I

Having thus described the construction of my improved drainage and relief valve, the operation thereof will now'be described.

When the throttle valve 17 is opened to start the engine, high pressure steam will enter through the pipe 16 and will act against the larger end of the differential piston to move the piston to the position shown'm 1 1g. 2, closlng the drainage-opening 18. The differential piston will remain 1n this position during the normal operation of the engine.

I As soon [as the throttle is closed, however, the pressure in the pipe 16 will fall and the compression in the engine as the engine is drifting and be' sides of the let 18, thus tak wvhentlie throttle valve 17 dilferential piston will be equalizedthrough the restricted ipassage which also serves to connect the pipe 16 to the drainage outin'g care oi? an'r eond, amnion in the pipe 16 a'd pre" u-iting trees-big thereo t when the engine dead. The steam or'other fluid under pressure remaining in the pipe 16 when the valve l7 is closed gradually escapes through the restricted passage 23. slowly escapingfluid priwents too abrupt n iovenient oi the pistoi'i 20 to. the epen position shown in Fig. 3, the Gfi'lGCl; of the structure including the r ricted passage being similar tovthat'ot a dash pot or pneumatic cushion. At the same time, the opening 1 8 freely connct' rd bythe pipe let to thecylindcr clearance and provides-effective drainagetherefor. i i

Furthermore, the opening 18 acts as a vent for the cylinder while running idle, preventing theformationo t a vacuum therein, This is of considerable in ortance, as it prevents the usual back di through the exhaust connection to the smolte pipe. This back draft objectionable for several reasons and particularly on account otthe clogging of the valves and other partsfot the engine by soot'brought in through the exhaust. I

It sometimes happens that a considerable amount of water will accumulate in the steam connections if the engine is left standing, and this water may cause serious damage when the engine is started. Iii-Water should aceun'iulate in,the connections to a cylinder having my improved valves in such quantity as to fill the clearance space, the pressure of the engine 1 ton uponthe water would act against the differential piston 20, overcoming the prcssure of the stean'i the large end of the dilferential. piston 20 and permitting the escape of the. water through the drainage opening 18. Ordinarily, however, my drainage and relief valve itself prevents any injurious accumulation of, water. 7 i Y If for any reason it is desirable to prevent closing of the drainage and relief valves is opened to start the engine, or in the event; of excessive leal agepast the closed valve 17, pressure may be admitted to the pipe 25, through the vhand valve 26-and the piston in the valve 24 will be moved to close the pipe 16. This prevent-s tlie building up of pressure behind the pistons 20 in the chambers 12 and causes any excess of pressure in thepipes llto move the pistons to the open position shown inl ig. 3 and to retain the pistons in such position, It will be understoodthat the pressure in the exhaust passages and clearance spaces of the engine is alwaysabove atmosphericpressure when the engine is in operation and the piston is movingtoward a given exhaust passage or clearance space. This increased pressure, l'ioivever, is intermi intent and cannot in the chamber 12 m'i'ttent action and also on account of vthe small diameter. of the restricted passage 23 and the relatively large diameter of the open exhaust passage ,18. v i

llaving thus described my invention and the uses and advantagesthereof, I do not Wish to be'otherwise limitedthanas set forth in the claims, but what I claih'i is l. A draii'iage and relieif' valve comprising a'valve casing having a chamber, a connection therefrom to the engine cylinder, a second connection therefrom to ,a supply of fluid under pressure, said chamber having a drainage outlet between said connections, and a diflerential piston freely slidable in said chamber between said connections and controlling said outlet, said ditfcrential'pis ton having its smaller surfacev cylinder connection, and said drainage and relief valve being provided witha muchvrcstricted passage permitting slow escape of fluid from said valve chamber and thereby providinga gradually decreasing fluid ion tor-said differential piston.

2. A drainage and relief valve comprising a valve casing having a chamber, a connection therefrom to the engine cylinder, a secfluid under pressure, said chamber having a drainage outlet between said connections, and a differential piston freely slidable in said chamber between said connections and controlling said outlet, said differential piston having a smaller surface adjacent the cylinder connection, and said drainage and relief valve having a restricted passage cots necting the parts of the valve chamber on the opposites-ides of the ,difierential piston.

A drainage andreliel valve comprising a valve casing having a chamber, a connection therefrom to the engine cylinder, a second connection therefrom to a supply of fluid under pressure, said chamber having drainae outlet between said connections, and a differential piston freely slidable in. said chamber between said connections and controlling said outlet, said differential piston having a restrictedopening extending therethroughand connecting the parts oi the valve chamber on opposite sides of saididitferential piston.

flxed my signature.

mi NK 0; MILLER.

bur-1:61; up a high pressin-e on account of its 1nter-' adjacent the cush- Hiii 

